Nippon Graphite Industries, Ltd.

Tadaaki Isono

Katsuhiro Murata

Mitsumasa Shibata

Toru Hatakeyama

An adhesive is applied onto a flexible resistive film 1 and dried to form an adhesive layer 2. A metal foil 3 is contacted onto the layer 2, which is subjected to a heat and pressing treatment. The foil 3 is polished. An ultraviolet light curable ink is applied on the foil 3 and dried to form a first layer 4. A negative film is placed on or over the layer 4 and ultraviolet light is irradiated thereto through the film so that the layer 4 is cured. Uncured portions of the layer 4 is removed so that cured portions thereof remain and the foil 3 is exposed between the remaining cured portions. The metal foil 3 is subjected to an etching treatment to remove exposed portions of the foil 3 so that unexposed portions of the foil 3 remain and form conductors 3A. The cured portions of the layer 4 is removed from the conductors 3A. A metal plating film 5 is formed on each conductor 3A to form each electrical conductive circuit 9. An ultraviolet light curable ink is applied on the layer 2 and dried to form a second layer 7. Ultraviolet light is irradiated to the layer 7 through the film 1 so that the layer 7 is cured in gaps 6 between the circuits 9. Uncured portions of the layer 7 is removed so that the circuits 9 are exposed and cured portions of the layer 7 remain in the gaps 6. The cured portions of the layer 7 is subjected to a heat treatment. The resulting flexible circuit board comprises the film 1, the adhesive layer 2, the circuits 9 and cured films 8 filling the gaps 6.

Method for producing flexible circuit boards

A flexible circuit board device for connecting to an electronic device comprised of a flexible circuit board made from flexible resistive film, an adhesive layer formed on the flexible resistive film, electrical conductive circuits formed on the adhesive layer and cured films filling the gaps between the conductive circuits. The electrical conductive circuits are formed of conductor metal foil and a plating film covering the surface of the conductor.

Flexible printed circuit board comprising conductive circuits, an

Longitudinally fine striped type heat seal connector member having a layer of an anisotropic press heat bonding agent which has satisfactory connection and reliable electrical conductivity in height or length direction as well as reliable electrical insulative property in lateral direction is provided by the method of the present invention, which is relatively simple in producing the layer of the anisotropic press heat bonding and which can dispense with some strong alkali or the like etching agent.

Method of producing longitudinally fine striped type heat seal connector

A method of producing electrically conductive anisotropic heat sealing connector members comprising, a process A of preparing an electrically conductive anisotropic suspension liquid type paint, applying the conductive paint on a surface of a flexible electrically insulative substrate film to form an electrically conductive circuit of longitudinal thin stripes pattern, and drying the applied conductive paint on the substrate film; a process B of preparing an electrically insulative heat-bonding suspension liquid type paint, applying the insulative paint wholly on the surface of the substrate film including both the longitudinal thin stripes pattern formed by the process A and the remaining portion of the substrate film, and drying the applied insulative paint on the substrate film to form a press heat bonding layer; and a process C of severing the applied and dried substrate film prepared by the processes A and B to desired length and width sizes to produce electrically conductive anisotropic heat sealing connector members.

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Ohtsu, Japan

Tadaaki Isono